There are many cases where a variety of aquatic organisms, including animals such as oysters, hard-shelled mussels, barnacles, etc., plants such as kelp, bacteria and the like, are attached to and propagate on the surfaces of bottoms of ships, underwater (marine) structures, and fishnets, which are exposed to water such as rivers or oceans for a long period of time, undesirably damaging the outer appearance of the ships or underwater structures and deteriorating the functionality thereof.
In an example, once marine microbes are attached to the marine structures of tidal current power plants, they may rapidly propagate, and a variety of marine organisms may also be attached by means of such microbes, undesirably lowering the power generation efficiency and promoting corrosion, resulting in serious negative effects on the safety of the marine structures.
In particular, when aquatic organisms become attached to or propagate on the bottoms of the ships, the total surface roughness of the ships may increase, undesirably reducing sailing speed and increasing fuel consumption. Furthermore, when bacteria, slime (sludge material) or large sessile organisms are attached to underwater structures, putrefaction or damage to anti-corrosive films may occur, undesirably deteriorating the strength or functionality of the underwater structures, whereby the lifetime thereof may be remarkably shortened. Hence, such aquatic organisms need to be removed from the bottoms of the ships. However, this work requires a lot of labor and takes a long time.
In order to prevent such damage, the bottoms of ships or underwater structures may be coated with various antifouling paints. Such antifouling paint may be applied on the surface of the ship under the surface of the water so as to prevent underwater animals and plants from being attached to the surface of the ship hull, thus reducing the frictional resistance of the ship. Recently, paints containing an organotin compound, mercury, a copper compound, etc., which are toxic to underwater organisms, have been used, but are gradually released from the surface of the ship hull into the water, and are thus regarded as a pollutant that negatively affects underwater organisms. Accordingly, the use of conventional toxic antifouling paints is restricted all over the world. For example, organotin compounds are very toxic, thus incurring marine pollution, the generation of mutant fish and shellfish, and harmful effects on ecosystems through the food chain.
With the goal of solving such problems, the present invention is intended to provide an environmentally friendly antifouling paint for preventing corrosion and the pollution of marine microbes. In the present invention, a conducting polymer having anti-corrosion functionality is primarily encapsulated with amphiphilic functional nanoparticles having antifouling properties, after which secondary microcapsules are formed using a hydrogel so that the conducting polymer contained in the nanoparticles is slowly and continuously released or is released in a specific environment, thereby improving anti-corrosion and antifouling properties.
In particular, the conducting polymer particles, which are positioned internally, may exhibit anti-corrosion functionality, ultimately maximizing anti-corrosion and antifouling effects through a single coating process.